The present invention relates to the field of producing low flow rates of feedstock vapors utilized in the manufacturing of silica glass. In particular, the invention is especially suited for use in the manufacture of planar optical waveguides and lightwave optical circuits.
Silica soot is deposited in thin layers on planar surfaces in the manufacture of lightwave optical circuits. The deposited soot is sintered and consolidated into silica glass that form the core and cladding glasses that make up the optical waveguides in optical circuits. U.S. patent application Ser. No. 08/581,186 filed Dec. 12, 1995, Bandwidth-Adjusted Wavelength Demultiplexer, by Denis M. Trouchet, the disclosure of which is hereby incorporated by reference discloses such a planar optical circuit which functions as a wavelength demultiplexer.
Previous feedstock vapor producing systems used in the manufacture of planar optical waveguides and circuits have used a complicated system of multiple bubblers with an individual bubbler for each of the chemical components of the feedstock vapor. Prior art feedstock vapor producing systems have been complicated and unreliable in producing a low volume flow rate of feedstock vapors. Prior art feedstock vapor producing systems have been found to produce an undesirable pulse in the stream of soot emerging from the flame of the conversion site burner and have difficulties in delivering a consistent low flow rate of feedstock vapors.
In light of the foregoing, there is d need for a method and apparatus for producing low flow rates of feedstock vapors which overcomes the difficulties and shortcomings of the prior art.
Accordingly, the present invention is directed to a system for producing a low flow rate of feedstock vapors utilized in the manufacturing of optical waveguides such as planar optical circuits that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
The features and advantages of the invention are set forth in the description which follows and in part will be apparent from the description or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the methods and apparatus particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the invention as embodied and broadly described, the invention includes a method of producing feedstock vapors in the manufacturing of optical waveguides using the steps of providing a constant flow of a liquid feedstock, mixing the flow of liquid feedstock with an inert injector gas, providing a vaporizer chamber, expelling the mixture of liquid feedstock and injector gas from an injector orifice, and into the vaporizer chamber, flowing a carrier gas into the vaporizer chamber and by the injector orifice and through the expelled mixture of liquid feedstock and injector gas. The inventive method includes the further steps of vaporizing the liquid feedstock into a feedstock vapor and delivering the feedstock vapor to a conversion site where it is converted into a silica soot which produces a silica based glass.
In another aspect the invention includes an apparatus for generating and delivering feedstock vapors in the manufacturing of silica glass which includes a means for providing a constant flow of a liquid feedstock, a means for providing a flow of an injector gas, and a mixer for mixing the liquid feedstock with the injector gas. The apparatus further includes a longitudinal injector tube for communicating the mixture of liquid feedstock and injector gas from the mixer and into a vaporizer chamber and a means for flowing a carrier gas close to the injector tube, preferably said flow starting before entry into the vaporizer chamber, and into the vaporizer chamber wherein the injected liquid feedstock is vaporized into a feedstock vapor. The apparatus includes a delivery conduit for delivering the feedstock vapor to a silica glass manufacturing site wherein the feedstock vapor is converted into silica soot.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention together with the description serve to explain the principles of the invention.